How much will burn?

Discussion in 'Reloading' started by edge, Jun 6, 2006.

  1. edge

    edge Well-Known Member

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    Are there any reasonably accurate ways to determine how much powder will burn in a certain barrel length?

    Here is my situation:

    I made a smokeless muzzleloader out of a Savage 110 action and added a #7 .458 barrel with a breechplug that uses a 45 acp case for the primer.

    I am trying to work up a load for a 150 grain 30 cal SMK/Accubond/SST/A-Max
    The sabot weighs 42 grains bringing the total weight to 192 grains.

    My main problem is with choice of powders.

    1) I need a stick powder so that it does not fall through the hole in the breechplug;

    2) the bullet/sabot offers VERY little initial resistance;

    3) 22 1/2 inches of usable barrel length, this INCLUDES the powder area;

    4) I would prefer to not duplex powder. It has worked well but if one powder will work I prefer that.

    5) 50,000 psi working load would be preferred (55k max)

    Now the problem:

    When I get a powder to a meaningful load the muzzle blast becomes excessive and the accuracy goes to heck ( presumably due to not burning the powder soon enough).

    60+ grains of H4198 is about max
    65 grains of N120 the same( I thought that this should be a good range of powder).

    N110 was still good @ 60 grains but I ran out of time.

    So my real question is, do I just proceed by trail and error in figuring if a powder will burn completely in this short tube?

    Any help will be greatly appreciated.

    edge.
     
  2. Varmint Hunter

    Varmint Hunter Well-Known Member

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    I'm just guessing but wouldn't a heavier projectile enhance powder burn within the barrel?

    Maybe a tighter sabot/bullet fit would also provide more complete combustion.

    Be CAREFUL because the whole idea sounds a bit risky unless you have pressure testing equiptment.

    /ubbthreads/images/graemlins/crazy.gif
     

  3. edge

    edge Well-Known Member

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    Thanks for the concern, I have been shooting a Savage Muzzleloader( 50 cal)since 2001. Most loads use N110, 4759, RL-7, 2400, 5744
    I was not really happy with the light barrel and that is why I beefed it up to a #7 contour with a 1 1/4 inch diameter.

    Yes, a heavier bullet would make things easier, but would also reduce range too. I am limited by a 1:14 twist.

    I can get to 1000 yards, but just barely, and would like a little more cushion.

    edge.
     
  4. davewilson

    davewilson Well-Known Member

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    when you say offers very little "initial" resistance,are you saying that it gets tighter as it goes down the barrel? if this is the case,by that i mean the bore diameter is smaller at the breach end than it is towards the muzzle,that barrel will probably never shoot very well.

    other than that, i would also say you need a bigger bullet.get a sabot that would shoot the 338 bullets, a 225 accubond might work in a 14.maybe it wouldn't but a 168 or 165 in 30 cal would.
     
  5. edge

    edge Well-Known Member

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    Dave Wilson,

    What I meant is that since the bullet does not get swagged into the bore, which takes 1,000 or more pounds of pressure, the bullet starts moving quicker and at a lower pressure.
    Duplex may be the best way to get much past 3,000 fps without raising the pressure beyond my comfort zone. N110 would seem to be the fast side to reach 3100, but N120, which I think should be ideal, may need more pressure than a 192 grain sabot/bullet can provide.

    edge.
     
  6. davewilson

    davewilson Well-Known Member

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    Edge, i understand now. you're simply comparing the difference between a conventional jacketed bullet with a sabot in a muzzleloader.i thought you meant the bullet started easy and got more difficult as it went down the barrel when you were seating it.

    if i understand this right,you're using a pistol primer, rifle powder and bullet.might be a little easier to get a 30-06 and some reloading dies! /ubbthreads/images/graemlins/smile.gif
     
  7. Black Diamond 408

    Black Diamond 408 Well-Known Member

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    I have been making smokless muzzle loaders for years, most of them are traditional looking using the Remington Rollingblock actions. I have also used H&R single shot shotgun actions with a Douglas 50cal bbl. Most all of my customers have settled on 25-27grns of 2400 powder with the sabo. 50cal mind you. 300yd accuracy is very good for this type of rifle. Some loads through the chrono were right at 2000fps. My rifles use a 209 shotgun primer, the primers are covered and no powder will get through the small breech plug.

    Dave
     
  8. edge

    edge Well-Known Member

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    [ QUOTE ]
    SNIP

    if i understand this right,you're using a pistol primer, rifle powder and bullet.might be a little easier to get a 30-06 and some reloading dies! /ubbthreads/images/graemlins/smile.gif

    [/ QUOTE ]

    I have two primers that I use in the 45 ACP cases. I use LR primers mainly, but had initially bored out the primer pocket to use a 209 primer. The 209 can be replaced without a press but requires more machining.

    edge.
     
  9. edge

    edge Well-Known Member

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    Black Diamond 408, your rifles sound very interesting. I have a great hunting ML, it was a Savage ML-II that I put a 1:20 twist 505 Gibbs Krieger barrel on. It will consistently shoot 150 grain 8mm bullets at just under 3,000 fps sub moa.
    The problem is that with a 1:20 twist I can't get a bullet to 1000 yards and still remain stable. I had this spare barrel and too much free time /ubbthreads/images/graemlins/smile.gif

    edge.